1. Field of the Invention
The present invention generally relates to a method for forming a carbon-doped silicon oxide (SiOCH) film on a substrate, particularly to a method for forming a SiOCH film modified by organoaminosilane annealing, for example.
2. Description of the Related Art
With miniaturization of wiring pitch of large scale integration (LSI) devices, signal delay due to the resultant increased wiring capacitance has become a problem. In order to reduce the wiring capacitance, attempts to reduce the dielectric constant of interlayer films have been implemented, and as a result, porous SiOCH films having pores in the films have been utilized.
Recently, instead of the damascene process used for conventional Cu wiring, a process of forming metal wires and embedding low-K film (e.g., a SiOCH film) between them is considered. For the process, a method of forming highly flowable film at a low temperature is required.
In forming flowable low-k film, it is necessary to remove alcohol and hydrocarbon included in the film after film formation by conducting curing such as UV or thermal annealing so as to form strong Si—O bonds. Flowable low-k films include large quantities of hydrocarbons, alcohols, unreacted precursors, and Si—OH bonds. Due to the occurrence of desorption or cross-linkage of these components during curing, extensive film shrinkage occurs. As a result, because voids are generated in the film which is embedded in trenches with a narrow pitch, the functionality of the insulating film is lost, which becomes a problem.
Additionally, if, in order to improve stability of the film, the duration of UV light curing is prolonged, film shrinkage progresses more, and it may result in disconnection of wires, collapse of wires, and cracking of the film. Thus, technology which enables a reduction of film shrinkage is in great demand for improving the film quality.
Any discussion of problems and solutions involved in the related art has been included in this disclosure solely for the purposes of providing a context for the present invention, and should not be taken as an admission that any or all of the discussion were known at the time the invention was made.